Imaging apparatus

ABSTRACT

Upon detection of the attachment of a recording medium, an image signal obtained by taking a picture and condition information representing a condition in which the picture is taken are read out form a memory in an image pickup apparatus and recorded on the recording medium. The apparatus is also arranged in such a manner that the condition information recorded on the recording medium may be transferred to the memory. With this arrangement, it becomes possible to process the image signal by using the condition information stored in the memory, even in a situation in which the recording medium is detached. Furthermore, it becomes possible to inherit the condition information even when the recording medium is exchanged.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to imaging apparatus, moreparticularly, to a manner of dealing with control data in signalprocessing performed in reproducing apparatus or recording apparatus.

[0003] 2. Description of the Related Art

[0004] Various types of apparatus are known for recording andreproducing pictures in which the image signals of objects are producedby a solid-state image sensor such as a CCD, then aftersignal-processing these image signals, they are recorded on a recordingmedium such as a magnetic tape and a magnetic disk. As an example, letus take an electronic still camera which records an object image on arecording medium as a still image. Control of white balance (hereafterreferred to as WB) for color image signals obtained by taking thepicture is an example of signal processing performed on the imagesignals depending on the data representing the condition under which apicture is taken.

[0005] Two known technologies for automatically performing WB controlare an external WB method and an internal WB method called a TTL(Through the Lens) method.

[0006] In the external WB method, for example, the ratio of the red (R)component to the blue (B) component is determined for the light passingthrough the filters disposed on a front surface of a camera and theresulting ratio is used as WB data. In the TTL method, on the otherhand, a picture of a reference object is taken before taking a pictureof an actual object and the image signal of the reference object is suedto perform WB control.

[0007] Comparing these two methods of WB control, the TTL method isgenerally more advantageous than the external WB method with regard tothe size and cost of apparatus. In either case, WB control is carriedout on the image signal obtained by taking a picture, and then the imageis recorded on a recording medium as image signals color signals ofwhich are controlled in gain to a desired value.

[0008] One possible arrangement is to record the data for use in signalprocessing such as WB control on a recording medium together with normalimage signals obtained by taking a picture. This arrangement is usefulto reduce the requirement of memory capacity of the apparatus and toreduce the processing time required for taking a picture, because the WBcontrol may be performed when the picture is reproduced.

[0009] However, in the case of such an electronic still camera in whichthe control data is recorded on a recording medium, if the recordingmedium is detached from the camera, the WB control data becomes notavailable, and thus it becomes impossible to perform WB control.

[0010] Furthermore, the WB control data associated with even the samereference object will be different depending on the season and the timewhen the WB data is produced, and also depending on the location wherethe WB data is produced. As a result, it is very difficult to makeproper utilization of the WB control data which is recorded on therecording medium.

[0011] On the other hand, while the TTL method has generally anadvantage in the size and cost over the external WB method, in somecases it is impossible to perform as accurate control as required. Forexample, when the object has a large magnitude of vivid colorcomponents, the gain control of the color signals is performed such thatthe vivid color components are suppressed, and thus the reproductionfrom image signals obtained by taking a picture lacks vividness incolors.

SUMMARY OF THE INVENTION

[0012] In view of the above, it is an object of the present invention tosolve the above-described problems and to provide an imaging apparatusin which control data is produced based on state data with regard toimage signals representing the condition under which a picture is taken,and the resulting control data as well as image signals obtained bytaking the picture is recorded on a recording medium, whereby it becomespossible to use the control data more often and it also becomes possibleto increase the recording capacity of image signals.

[0013] To achieve the above object, one aspect of the present inventionprovides an imaging apparatus comprising image pickup means, firstmemory means capable of storing an image signal outputted from the imagepickup means and condition information representing a condition in whichthe image signal is picked up by the image pickup means, second memorymeans capable of storing the image signal outputted from the imagepickup means and the condition information, the second memory meansbeing detachably attached to the apparatus, and control means forcontrolling the condition information so as to be transferred betweenthe first memory means and the second memory means.

[0014] Additional objects and features of the present invention will bemore readily apparent from the following detailed description when takenin conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015]FIG. 1 is a block diagram showing a basic configuration of anelectronic still camera in accordance with first and sixth embodimentsof the present invention;

[0016]FIG. 2 is a schematic representation of a display of a viewfinderfor use in an electronic still camera shown in FIG. 1;

[0017]FIG. 3 shows the appearance of the white balance mode selectionswitch for use in an electronic still camera shown in FIG. 1;

[0018]FIG. 4 is a flow chart of the operation with regard to the whitebalance control in an electronic still camera shown in FIG. 1, mainlyillustrating the operation of a system controller;

[0019]FIG. 5 is a more detailed flow chart illustrating a routine ofwhite paper mode setting shown in FIG. 4;

[0020]FIG. 6 is a more detailed flow chart illustrating a setting moderoutine shown in FIG. 5;

[0021]FIG. 7 is a block diagram showing a second embodiment inaccordance with the present invention;

[0022]FIG. 8 is a block diagram showing a configuration of a camera unitof the second through fifth embodiments in accordance with the presentinvention;

[0023]FIG. 9 is a schematic representation illustrating the process forreading signals in the apparatus shown in FIG. 7;

[0024]FIG. 10 is a block diagram showing third and fifth embodiments inaccordance with the present invention;

[0025]FIG. 11 is a schematic diagram showing multiple picturereproduction in accordance with the fourth embodiment of the presentinvention.

[0026]FIG. 12 is a schematic diagram showing multiple picturereproduction in accordance with the fifth embodiment of the presentinvention;

[0027]FIG. 13 is a schematic diagram showing multiple picturereproduction in accordance with the fifth embodiment of the presentinvention;

[0028]FIG. 14 is a flow chart showing the operation with regard to whitebalance correction in accordance with the sixth embodiment of thepresent invention;

[0029]FIG. 15 is a block diagram showing a seventh embodiment inaccordance with the present invention;

[0030]FIG. 16 is a schematic diagram showing a configuration of a colorfilter arranged with additive complementary colors;

[0031]FIG. 17 is a graph showing an example of white balance data;

[0032]FIG. 18 is a block diagram showing another configuration inaccordance with the seventh embodiment of the present invention;

[0033]FIG. 19 is a schematic diagram showing a configuration of a colorfilter with RGB arrangement: and

[0034]FIG. 20 is a block diagram showing a further configuration inaccordance with the seventh embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0035] Now, a first embodiment of the present invention will bedescribed below.

[0036]FIG. 1 is a block diagram showing a basic configuration of anelectronic still camera in accordance with the first embodiment of thepresent invention.

[0037] In FIG. 1, there are shown a camera lens 1, a motor 2 for drivingthe lens 1, a controller 3 of the motor 2 for driving the lens 1, anelement 4 such as a shutter and diaphragm for controlling the amount oflight, and a solid-state image sensor 5 such as a CCD. There are alsoprovided a sample-and-hold circuit 6 for sampling and holding signalsoutputted from the solid-state image sensor 5, an analog-to-digital(A/D) converter 7 for converting the analog output signals from thesample-and-hold circuit 6 into digital signals, a memory 8 such as DRAM,and a memory controller 9 for controlling the operation of reading datafrom the memory 8 and writing data to the memory 8 and for controllingthe refreshing operation of the DRAM.

[0038] A pulse generator 10 is also provided for generating a timingsignal for use in driving the solid-state image sensor 5, asample-and-hold pulse for the sample-and-hold circuit 6, and a drivingpulse for the A/D converter 7. Furthermore, there are provided a systemcontroller 11 for controlling the operation of the whole system in theapparatus, and an interface 12 between a recording medium 13 and acamera body, which will be described later in more detail. A hard diskis used as the recording medium 13.

[0039] There are also shown a standby switch (SW1) 14 for making acamera stand by for taking a picture, a picture-shooting switch (SW2) 15for commanding the camera to take a picture, an electronic or opticalviewfinder 16 detachably attached to the camera, a white balance circuit17 for performing WB adjustment, a WB mode selection switch 18 forselecting the WB mode, an LED 19 for indicating that the WB mode is setby the above WB mode selection switch 18 to a white paper mode whichwill be described later in more detail, a white-paper shooting switch 20for giving the command to take a picture of white paper so as to obtainthe color temperature information for use in WB control, a mediumdetector 21 for determining whether the recording medium 13 is attachedto the camera body, a clock device 22 for counting a time and date, anda location detector 23 for determining where the electronic still camerais located by means of electromagnetic waves received from satellites.

[0040] In this embodiment, it is assumed that the WB control is carriedout by the external WB method, and there are further provided a colorsensor 24 for detecting color components in ambient light so as toobtain WB control data, a transfer switch 26 for transferring the WBcontrol data obtained by taking a picture of white paper (hereinafterreferred to as white paper WB data) from the hard disk 13 used as arecording medium to the memory 8 in the camera body, and an imageprocessor 27 for performing the processing such as white balancecorrection and gamma correction on color image signals obtained bytaking a picture.

[0041] Now, the signal flow in the electronic still camera in accordancewith the present embodiment of the invention will be described below.

[0042] When a picture is taken to obtain the signal of an image (stillimage), the image sensor 5 outputs the signal, which is sampled and heldby the sample-and-hold circuit 6, thus supplying the color image signal.Then, the color image signal is converted into a digital signal by anA/D converter 7.

[0043] The color image signal converted into a digital form istemporarily stored in memory 8. The image signal stored in the memory 8is processed by the image processor 27, and will be finally recorded onthe recording medium 13. There may be various options regarding when theimage processor 27 performs its operation. This operation timingadaptable for the electronic still camera of the present embodimentdepends on the configuration of the camera. These include the followingoptions:

[0044] (1) The image signal (data) stored in the memory 8 is read outand processed by the image processor 27. The resulting signal is storedagain in the memory 8. Then, the image signal stored in the memory 8 isread out again and recorded on the recording medium 13 via the interface(I/F) 12.

[0045] (2) The image signal stored in the memory 8 is read out andprocessed by the image processor 27. Then, the resulting signal isrecorded on the recording medium 13 via the I/F 12.

[0046] (3) The image signal stored in the memory 8 is read out anddirectly recorded on the recording medium 13 via the I/F 12. The imagesignal is reproduced from the recording medium 13 via the l/F 12 and itis stored in the memory 8 again. Then it is read out again and processedby the image processor 27. The resulting signal is re-stored in thememory 8 again. Finally, it is read out again and recorded on therecording medium 13 again via the I/F 12.

[0047] (4) The image signal stored in the memory 8 is read out anddirectly recorded on the recording medium 13 via the I/F 12. The imagesignal is reproduced from the recording medium 13 via the I/F 12 and issupplied directly to the image processor 27 so as to perform therequired processing. The processed signal is recorded again on therecording medium 13 via the I/F 12.

[0048] (5) The image signal stored in the memory 8 is read out anddirectly recorded on the recording medium 13 via the I/F 12. The imagesignal is reproduced from the recording medium 13 via the I/F 12 and issupplied directly to the image processor 27 so as to perform therequired processing. The processed signal is stored again the memory 8and then it is read out again and recorded again on the recording medium13 via the I/F 12.

[0049] (6) The image signal stored in the memory 8 is read out anddirectly recorded on the recording medium 13 via the I/F 12. The imagesignal is reproduced from the recording medium 13 via the I/F 12 and isstored again in the memory 8. Then the signal is read out again from thememory 8 and is processed by the image processor 27. The resultingsignal is recorded again on the recording medium 13 via the I/F 12.

[0050] The flow of the signal in WB control, which is one ofcharacteristic features of the present embodiment, will be describenext. The image data for one picture obtained by taking a picture ofwhite paper is stored in the memory 8. Then, the image processor 27accesses this image data for one picture and extracts portions of theimage data. This extracted data is stored again as white paper WB datain the memory 8. The extraction method to generate white paper WB datamay be any method by which the total required amount of information canbe reduced. Such methods include (a) extracting the image data for oneline every several lines from the image data for one picture, (b)extracting only central portion of the image data, (c) extracting apixel data every predetermined constant number of pixels from the wholeof the image data for one picture.

[0051] The white paper WB data obtained in this way is transferred fromthe memory 8 to the hard disk 13 via the I/F 12 as will be describedlater in more detail. This leads to the reduction in the amount of thewhite paper WB data recorded on the hard disk 13, which further leads toavoidance of the great reduction in recording capacity for color imagesignals obtained by taking actual (usual) pictures.

[0052] When a still image is taken in the white paper mode, the imagesignal corresponding to the still image is stored in the memory 8. Theimage processor 27 gets this image signal and also reads the white paperWB data stored in the memory 8 or recorded on the recording medium 13.Then, the image processor 27 corrects the white balance of the imagesignal corresponding to the still image by using color temperatureinformation which is formed from the white paper WB data. The timing ofcorrection may be selected from the options (1)-(6) described above.

[0053] The color sensor (WB) 24 provides its output to the WB circuit17, and thus the color temperature information (outside data) is alwaysavailable. When a still image is taken in the automatic mode, thisoutside data is inputted into the system controller 11 and furthersupplied to the image processor 27 via the memory controller 9. Asdescribed earlier, the image processor 27 reads the image signalcorresponding to the still image stored in the memory 8 and corrects itsWB by using the outside data. This timing of correction may also beselected from the options (1)-(6) described above.

[0054]FIG. 2 shows a display screen of the viewfinder 16 shown inFIG. 1. In FIG. 2, there are shown LEDs 31, 32, and 33 used forindication. The LED 31 turns on when the WB mode selection switch 18 isset to the white paper mode. The LED 32 turns on when the WB modeselection switch 18 is set to the setting mode. The LED 33 turns on whenthe generation of the white paper WB data has been completed.

[0055]FIG. 3 shows the appearance of the WB mode selection switch 18. Asshown, this switch is of the dial type and the WB control mode can beset to any one of automatic, manual, white paper, and setting modes byrotating the dial so that the arrow points the corresponding positionhaving the mark “AUTO”, “MANUAL”, “WHITE PAPER”, or “SET”. This dialswitch functions as a jumping back switch when the dial switch isswitched from the “WHITE PAPER” position to “SET” position. Thus, the“SET” position cannot be maintained and the selection will automaticallyreturn back to “WHITE PAPER” unless the operator holds the dial at the“SET” position.

[0056] In addition to the white paper mode and the automatic modedescribed above, the WB control modes also include manual mode as can beseen. In this manual mode, WB control value is manually set to any oneof four levels, (the number of levels may be less or more than four), bymanual operation means (not shown). When the dial switch is set to “SET”position, the setting mode is selected in which information on the colortemperature can be generated by taking a picture of white paper with theoperation switch 20 for taking a picture of white paper. Thus, it ispossible to take a picture of white paper and to generate theinformation on the color temperature (white paper data).

[0057]FIG. 4 is a flow chart showing the operation associated with thewhite balance control in an electronic still camera shown in FIG. 1, inwhich the operation of the system controller 11 is mainly illustrated.FIG. 5 is a more detailed flow chart illustrating a routine for settingthe white paper mode shown in FIG. 4. FIG. 6 is a more detailed flowchart illustrating a setting mode routine shown in FIG. 5. Referring tothese flow charts shown in FIGS. 4-6, the operation with regard to theWB control will be described below.

[0058] The flow chart of FIG. 4 starts with step S101 when a powerswitch (not shown) is turned on. This step S101 determines whether thehard disk (HDD) 13 is attached or not, judging from the output of themedium detector 21. If the HDD 13 is not attached, then the operationmoves to step S107 which determines whether the white paper data isrecorded in the memory 8 installed in the camera body. If there is nowhite paper data recorded in the memory 8, then the operation returns tostep S101.

[0059] In step S107, if the conclusion is that there exists the whitepaper WB data recorded in the memory 8, then the routine enters intostep S108 to wait for the HDD 13 to be attached. After completion of theattachment of the HDD 13, the HDD 13 is started up in step S109, andthen in step S110, the white paper WB data stored in the memory 8 istransferred to the HDD 13 via the I/F 12. After that, in step S111, theHDD 13 is stopped. Then, the routine proceeds to step S102.

[0060] In the above steps, if the HDD 13 is not attached, this meansthat the camera is not in the operation of taking a picture or otherwisethe HDD 13 becomes full of data during operation of taking a picture andthere is no room for further data. In the latter case, it is possible todirectly use the white paper WB data detected previously. In this case,as will be described later, just prior to the detachment of the HDD 13,the white paper WB data recorded on the HDD 13 is transferred to thememory 8. Thus, when the HDD 13 full of data is detached, the whitepaper WB data is always left in the memory 8. In step S110, this whitepaper WB data is recorded on a HDD 13 which is newly attached.

[0061] If the conclusion in step S101 is that the HDD 13 is attachedalready, or if the HDD 13 has been attached newly, then decision is madein step S102 whether the WB mode selection switch 18 is set to the whitepaper mode. If the white paper mode is not selected, then whether the WBmode selection switch 18 is set to the automatic mode is determined instep S104. In these steps S102 and S103, the selection of the WB modeselection switch 18 is definitely determined, that is to say, it isdetermined which dial position of “WHITE PAPER”, “AUTO”, or “MANUAL” isselected. If it is detected in step S104 that the automatic mode isselected, then the WB control is set to the automatic mode in step S105.If it is concluded in step S104 that the automatic mode is not selected,then it is considered that the dial position is set to “MANUAL” and instep S105 the WB control is set to the manual mode described above.

[0062] If it is concluded in step S102 that the WB mode selection switch18 is set to the white paper mode, then the routine proceeds to stepS103 in which the white mode setting routine is carried out.

[0063] As shown in FIG. 5, in step S201 of the white paper settingroutine, it is determined first whether the camera is in usual operationmode for taking a picture. If the camera is in usual operation, then theroutine waits for completion of the usual operation. If the camera isnot in usual operation or if the usual operation has been completed, theroutine proceeds to step S202 in which the LED 31 blinks to indicatethat the WB mode selection switch 18 is set to the white paper mode.

[0064] Alternatively, in step S202, the LED 31 may be lit continuouslyinstead of blinking, or it may be arranged that a warning sound isgenerated. Otherwise, the combination of these may also be possible.

[0065] In a case where the white paper WB data is produced for the firsttime by taking a picture of white paper, no white paper WB data isrecorded on the HDD 13 or stored in the memory 8. Therefore, in stepS203, decision is made whether the white paper WB data exists in thememory 8 or on the HDD 13, and if there exists no such data, then theroutine proceeds to step S204 so as to perform the setting-mode routinein which the white paper WB data is surely established.

[0066] On the other hand, if the white paper WB data already exists inthe memory 8 or on the HDD 13, it is possible to perform the WB controlby using this white paper WB data. Thus, except for the case in whichthe conclusion in step S206 indicates that the WB mode selection switch18 is set to the setting mode, the routine proceeds to step S207 inwhich the WB control is set to the white paper mode, and then theroutine returns to the main routine.

[0067] When step S203 concludes that no white paper WB data exists inthe memory 8 or on the HDD 13, or when step S206 concludes that the WBmode selection switch 18 is set to the setting mode, the routine entersinto step S204 so as to perform the setting-mode routine.

[0068] In this setting-mode routine, the white paper WB data isestablished as will be described in more detail hereinbelow, then theroutine returns to the main routine.

[0069] Referring to the flow chart shown in FIG. 6, the setting-moderoutine will be described. In the first step of the setting-moderoutine, S301, the LED 32 blinks to indicate that the WB control is inthe setting mode. Then, in step S302, the routine waits for theoperation switch 20 used for taking a picture of white paper to beturned on. In this case, the decision is made in step S306 whether thewhite paper WB data exists in the memory 8 or on the HDD 13.

[0070] If no white paper WB data exists, it is required to newly producewhite paper WB data. Thus, in this case, the routine returns to stepS302 so as to further wait for the operation switch 20 used for taking apicture of white paper to be turned on. On the other had, if the whitepaper WB data already exists in the memory 8 or on the HDD 13, thismeans that the WB mode selection switch 18 is set to “SET” position,that is to say, it is desired to update the white paper WB data.However, if the operation switch 20 used for taking a picture of whitepaper is not turned on for a predetermined time, the data is notupdated. In this case, the routine proceeds to step S307 so as todetermine whether the counted value of the counter in the systemcontroller 11 reaches a predetermined value. If the counted value isless than the predetermined value, the value is incremented in stepS308. If the counted value reaches the predetermined value with no eventof turning-on of the operation switch 20 used for taking a picture ofwhite paper, then the routine proceeds to step S309 in which the counteris reset without any new setting of the white paper WB data, and thusthe routine automatically cancels the setting mode.

[0071] If, in step S302, the operation switch 20 used for taking apicture of white paper is turned on, the routine proceeds to step S303in which a picture of white paper is taken by operating the image sensor5 and other required devices so as to produce new white paper WB dataand the resulting data is stored in the memory 8. Further, in step S304,the information on the time and data obtained from the clock device 22,the information of the location on the earth obtained from the locationdetector 23 and the white paper WB data newly produced, are all togetherrecorded on the HDD 13 via the I/F 12.

[0072] After that, in step S305, the LED 33 turns on to indicate thecompletion of taking a picture of white paper. Again in this step S305,alternatively, the LED 33 may blink instead of continuously lighting, orit may be arranged that a warning sound is generated, or the combinationof these may also be possible.

[0073] After these steps are completed, the routine passes via step S309to step S310 in which the LED 32 used for indication that the WB controlis in the setting mode and the LED 33 used for indicating the completionof taking a picture of white paper are both turned off. Then, theroutine returns to step S206 in the white paper mode setting routine.That is to say, the routine returns to the main routine after the WBcontrol mode is set to the white paper mode.

[0074] In these steps described above, the WB control mode isdetermined. In this situation, by operating the standby switch SW1 (14)and the operation switch SW2 (15) for taking a picture, it is possibleto perform the usual operation for taking a still image in the specifiedWB control mode. That is to say, step S112 determines whether thestandby switch SW1 (14) is turned on. If the conclusion is positive, theroutine proceeds to step S113 so as to make the operation be in thestandby mode for taking a picture by operating autofocussing functionand autoirising function.

[0075] In this standby mode, step S114 determines whether the operationswitch SW2 (15) used for taking a picture is turned on. If the operationswitch SW2 is turned on, a still image is taken in step S116. Step S115detects the occurrence of turning-off of the standby switch SW1 (14)before the occurrence of turning-on of the operation switch SW2 (15) fortaking a picture. Upon this occurrence, the routine returns to stepS112. Step S117, determines whether both of the standby switch SW1 (14)and the operation switch SW2 (15) for taking a picture are turned offafter completion of taking a still image. If the conclusion is positive,the routine returns to step S101.

[0076] After the WB control mode has been set as previously described,step S118 determines whether the HDD 13 is attached to the camera body.If the HDD 13 is attached, decision is made in step S119 whether thetransfer switch 26 is turned on. If the conclusion is positive, theroutine proceeds to step S120. If the HDD 13 is not attached, or if thetransfer switch 26 is not turned on, then the routine returns to stepS101.

[0077] The transfer switch 26 is operated to transfer the white paper WBdata stored on the HDD 13 to the memory 8 before the HDD 13 is detachedfor exchange. When the transfer switch 26 is turned on, decision is madein step S120 whether the white paper WB data is recorded on the HDD 13.If there is no such data, no operation occurs and the routine proceedsto step S124. In step S124, when turning-off of the transfer switch 26is confirmed, the routine returns to step S112.

[0078] If step S120 concludes that the HDD 13 has the white paper WBdata, the routine proceeds to step S121 to start up the HDD 13. Further,in step S122, the white paper WB data recorded on the HDD 13 istransferred to the memory 8 via the I/F 12. After that, in step S123,the HDD 13 is stopped. Then, in step S124 if turning-off of the transferswitch 26 is detected, the routine returns to step S112.

[0079] After the white paper WB data recorded on the HDD 13 which isgoing to be detached for exchange is transferred to the memory 8 in thecamera body as described above, another HDD is attached. Then, in stepsS107-S111 as described above, the white paper WB data is automaticallytransferred to the newly attached HDD. Thus, the white paper WB data isinherited.

[0080] With the arrangement described above, even in a case where theHDD 13 is detached, the WB control data stored in the memory 8 can beused to perform the WB control. Besides, the WB control data can beinherited when the HDD 13 is exchanged. Thus, it becomes possible toincrease the opportunity to use available white paper WB data and italso becomes possible to increase the possibility of performing betterWB control.

[0081] When the white paper WB data is produced in the WB setting modefor the above electronic still camera, if a picture of the white paperis taken with illumination of a fluorescent lamp in a room, the flickerof the fluorescent lamp may be detected so as to reduce the influence ofthe flicker by setting the shutter to the proper speed depending on thedetected flicker. For example, the shutter speed may be set to aninteger multiple of the flicker cycle. Alternatively, when the flickercycle is given as a constant value such as {fraction (1/100)} sec. or{fraction (1/120)} sec., the shutter speed may be set to for example{fraction (1/20)} sec.

[0082] In the embodiment described hereinabove, an HDD is used as arecording medium. However, alternatively, a semiconductor memory card orother type magnetic recording medium may be also used in an imagingapparatus in accordance with the present invention.

[0083] In accordance with the present embodiment of the invention, asdescribed above, the WB control data is generated from the color imagesignal outputted from the image pickup means. When the attachment of therecording medium is detected, correspondingly the WB control data isread from the internal memory means and is recorded on the recordingmedium. In addition, the WB control data recorded on the recordingmedium may be transferred to the internal memory means. Thus, even ifthe recording medium is detached, the WB control data stored in theinternal memory means may be used to perform WB control. Besides, the WBcontrol data may be inherited when the HDD 13 is exchanged. Thus, itbecomes possible to increase the opportunity to use available whitepaper WB data and it also becomes possible to increase the possibilityof performing better WB control.

[0084] When the color image signal outputted from image pickup means isrecorded as WB control data on the recording medium, only a portion ofthe color image signal may be recorded as the WB control data so as tominimize the reduction in the recording capacity for color image signalsfor usual pictures.

[0085] Now, a second embodiment of the present invention will bedescribed hereinbelow.

[0086] In the first embodiment, the WB control data is generated andrecorded together with the image signals. However, in some cases, aspreviously described, sufficiently high accuracy control cannot beachieved. This second embodiment provides an imaging apparatus which canovercome this disadvantage.

[0087] In this embodiment, an electronic still camera will be takenagain as an example to which the present invention is applied. FIG. 7shows a video reproducing apparatus in accordance with the secondembodiment of the present invention.

[0088] In FIG. 7, there is shown an HDD 701 which is detachably attachedto the video reproducing apparatus and which is used as a videorecording medium. There are also shown a controller 702 for controllingthe whole of apparatus including the HDD 701, a memory 703 used forstoring the video signal read from the HDD 701 under the control of thecontroller 702, an adder 704 by which signals read from the memory 703are added to each other as described later, and a luminance signalprocessing circuit 705 for processing the signals outputted from theadder 704 so as to produce a luminance signal Y.

[0089] A color signal processing circuit 706 is also shown in FIG. 7 forproducing color signals R₁, G₁, and B₁ from the video signal providedfrom the adder 704. A variable gain amplifier 707 controls the gains ofrespective color signals R₁, G₁, and B₁ and outputs the resultingsignals R, G and B. There are also provided a matrix circuit 708 forperforming matrix processing on the color signals R, G, and B so as toproduce color-difference signals R-Y and B-Y, an encoder 709 forproducing a composite video signal from the color-difference signalsR-T, B-Y and the luminance signal Y described above, a D/A converter 710for converting the composite video signal to an analog signal, an adder711 for adding a synchronizing signal from the controller 702 to thecomposite video signal which has been D/A-converted, a driver 712 whichinputs the composite video signal added with the synchronizing signaland which operates under the control of the controller 702, a monitor713 for displaying a video image under the control of the driver 712,and an operation unit 719 used for operating various switches.

[0090] Furthermore, there are shown a data detection unit 714 whichdetects the designation data associated with WB, which will be describedlater in more detail, from the signal read from the HDD 701 so as toprovide the detected designation data to the controller 702, a colortemperature detection unit 715 for detecting the color temperature ofthe video signal from the previously described color-difference signalsR-Y and B-Y under the control of the controller 702, and a hold circuit716 for holding the detected color temperature which is used as the WBcontrol value for controlling the gain of the variable gain amplifier707.

[0091]FIG. 8 shows a camera unit for taking a picture of an object andfor recording the image of the object on the HDD 701 previouslydescribed. The HDD 701 is detachably attached to the camera unit. Afterthe image data associated with the pictures taken by the camera unit isrecorded on this HDD 701, the HDD 701 is detached from the camera unitand attached to the video reproducing apparatus shown in FIG. 7 toreproduce the images. Alternatively, the camera unit may be arranged inan integral form with the video reproducing apparatus.

[0092] In FIG. 8, there are shown a controller 720 for controlling thetotal system of the camera unit, an optical system 721 including a lens,a diaphragm and the like, an image pickup part 722 including a CCD usedas an image sensor. This CCD has color filters such as those shown inFIG. 9 arranged for each pixel. As shown, the color filter comprises twotypes of lines: one comprises Mg (magenta) and G (green) which arearranged alternatively, and the other one comprises Cy (cyan) and Ye(yellow) which are arranged alternatively, wherein the locationalternates between Mg and G line to line to form so-called checkeredarrangement with additive complementary colors.

[0093] There are also shown an A/D converter 723 for performing A/Dconversion on the signal obtained by photoelectric conversion with theimage pickup part 722, and a memory 724 such as a semiconductor memoryfor storing image data for one picture in the digital form obtained byphotoelectric conversion with the above CCD. Furthermore, there isprovided an adder 725 which adds the signal read from the memory 724 tothe designation data associated with WB from the controller 720 andwhich outputs the resulting signal so as to record it on the HDD 701. Anoperation unit 726 is also shown which has various switches including adesignation switch used for producing designation data.

[0094] Now, the operation in the above arrangement will be describedbelow.

[0095] In this embodiment, a plurality of pictures are taken with thecamera unit shown in FIG. 8 and a plurality of video signals thereof arerecorded on the HDD 701. One of these video signals is designated as areference video signal, which is to be used as reference to produce thecontrol data for WB control in reproducing process. Then, thedesignation data representing the above fact, the reference videosignal, and the location data representing the location thereof are alltogether recorded on the HDD 701. As for the other remaining videosignals, the designation data (corresponding to the location data of thereference video signal) designating the location of the video signalwhich is to be used as the reference video signal to perform WB controlwhen reproducing it, is recorded together with respective video signal.

[0096] In the above procedure, the signal obtained by taking a picturefor example to a neutral gray reference board or an object including alarge amount of white components is used as the reference video signal.

[0097] In reproduction, the reference video signal is taken from theabove plurality of video signals and it is reproduced so as to obtainthe WB control data. This control data is used to determine the gain ofthe variable gain amplifier 707. When the other video signals arereproduced, WB control is performed by using this WB control data.

[0098] Now, detailed descriptions will be given hereinbelow on theoperation of recording and reproducing.

[0099] In the camera unit shown in FIG. 8, the operation unit 726 has aswitch 726 a used for determining whether the signal which is about tobe obtained by taking a picture is designated as the reference videosignal used as the WB control data in reproduction. There is alsoprovided a switch 726 b which is used, in the case the switch 726 a isset such that the signal which is about to be obtained by taking apicture is not adopted as the reference video signal, to designate whichof video signals will be used as the reference video signal. Theseswitches may be set by an operator before taking a picture of an object.When a video signal is stored on the HDD 701, the informationestablished by setting these switches is provided as designationinformation from the controller 720 to the adder 725, and then thisinformation is recorded on the HDD 701 when the video signal isrecorded. With reference to FIG. 8, when a release switch in theoperation unit 726 is operated, the controller 720 controls thediaphragm in the optical system 721 and determines the exposure time soas to give a proper exposure to the CCD in the image pickup part 722. Inthis way, the optical system 721 and the image pickup part 722 arecontrolled. Then, the signal is read from the properly exposed CCD, andthe resulting signal is inputted to the A/D converter 723 in which theelectrical signal corresponding to an individual pixel of the CCD isconverted into a digital signal. The signal corresponding to the pixelof the CCD from the A/D converter 723 is inputted to the memory 724, andis stored temporarily in it.

[0100] Then, the signal is transferred from the memory 724 to the HDD701. Prior to the reading of a signal from the memory 724, thecontroller 720 outputs the designation data which represents whether thesignal being obtained at that time by taking a picture will be used asthe reference video signal in reproduction to produce the WB controldata and which represents the recording area (location) where thereference video signal to be used in reproduction is recorded in thecase in which the above signal obtained at that time by taking a picturewill not be used as the reference video signal. This designation datafrom the controller 720 is recorded on the HDD 701 at the prescribedrecording area (location). Then, the controller 720 controls the memory724 and reads the signal stored in the memory 724. Further thecontroller 720 records this signal on the HDD 701 at the prescribedrecording area via the adder 725.

[0101] As described above, the video signal obtained by taking a picturewith the camera unit is recorded on the HDD 701 together with thedesignation data associated with the WB control. Then, the HDD 701 onwhich the video signal is recorded is detached from the camera unit andattached to the video reproducing apparatus shown in FIG. 7 to reproducethe video signal. Now, this operation will be described below.

[0102] With reference to FIG. 7, when the operation unit 719 issues acommand to reproduce a certain video signal, the controller 702 readsthe signals from the HDD 701. The designation data with regard to the WBcontrol for the recorded video signals is read first. This designationdata is detected by the data detection unit 714 and is further inputtedto the controller 702.

[0103] Then, the controller 702 determines whether the video signaldesignated to be reproduced is the reference video signal. If thissignal is designated as the reference video signal, then the data ofthis video signal for one frame is read from the HDD 701 and stored inthe memory 703. The location data representing the recording area ofthis video signal is stored in the controller 702. Control is performedon the video data for one frame stored in the memory 703 so that thedata corresponding to two lines of the image sensor in the camera unitmay be read out at the same time.

[0104] More specifically, as shown in FIG. 9, when the first field isread out, a pair of lines 1 and 2, lines 3 and 4, . . . , or lines 2 n+1and 2(n+1) are read at the same time, and when the second field is readout, a pair of lines 2 and 3, lines 4 and 5, . . . or lines 2 n and 2n+1 are read out from the memory 703, and the signals read out are addedto each other with the adder 704. The output signal of the adder 704 isapplied to the luminance signal processing circuit 705 as well as to thecolor signal processing circuit 706. In the luminance signal processingcircuit 705, the luminance signal is generated from the input signalsassociated with Mg, G, Cy, and Ye, and the resulting signal is appliedto the encoder 709. On the other hand, the color signal processingcircuit 706 generates the signals R₁, G₁, and B₁ from the input videosignal and provides these signals to the variable gain amplifier 707.

[0105] In this situation, the controller 702 relieves holding operationof the hold circuit 716 which controls the gain of the variable gainamplifier 707 so that the output signal of the color temperaturedetection unit 715 is directly outputted from the hold circuit 716. Thatis to say, when the present video signal is processed successively afterthe previous video signal, the latest output signal which was used toprocess the previous video signal is still provided as the output signalfrom the color temperature detection unit 715, and this signal isapplied as the control input signal via the hold circuit 716 to thevariable gain amplifier 707. Gain control of the variable gain amplifier707 is performed on each amplifier associated with input signals R₁, G₁,and B₁ depending on each gain control signal.

[0106] Then, the gain-controlled R, G, and B signals are inputted to thematrix circuit 708 from the variable gain amplifier 707. The matrixcircuit 708 produces the R-Y and B-Y signals by using known matrixprocessing and outputs the resulting signals. The R-Y and B-Y outputsignals are inputted to the encoder 709 and also to the colortemperature detection unit 715. The color temperature detection unit 715performs integration of the R-Y and B-Y input signals over one fieldperiod, and updates via the hold circuit 716 the control signal for thevariable gain amplifier 707 every field. Thus, the gains for R, G, and Bsignals are controlled so that the integrated values of R-Y and B-Ysignals become nearly zero. That is to say, a control loop is formedthrough the variable gain amplifier 707, the matrix circuit 708, thecolor temperature detection unit 715 and the hold circuit 716, and thiscontrol loop functions such that the integrated values taken over aperiod of one field on R-Y and B-Y signals become nearly zero. Thus, theWB control is performed through this control loop.

[0107] The R-Y and B-Y signals as well as the Y signal from theluminance signal processing circuit 705 are inputted to the encoder 709,which produces the composite video signal. The produced composite signalis converted into an analog signal with the D/A converter 710. Then, inthe adder 711, the synchronization signal from the controller 702 isadded to the output signal from the D/A converter 710 and the resultingsignal is applied to the driver 712. The driver 712 outputs this signalas the video signal to be displayed on the monitor 713.

[0108] The operation is performed in a manner described above, when thevideo signal read from the HDD 701 is designated by its associateddesignation data as the reference video signal. On the other hand, whenthe video signal is not designated by its associated designation data asthe reference video signal, the operation will be performed in such away as will be described below.

[0109] In such a case, it is possible to use the location data recordedas the designation data representing the recording area where thereference video signal for the video signal read from the HDD 701 isrecorded. Therefor, the data detection unit 714 detects this locationdata. This detected location data representing the recording areaassociated with the video signal is compared with the location datarepresenting the recording area of the video signal stored in thecontroller 702, that is to say, the location data representing therecording area of the reference video signal which was previously usedto perform the WB control. If these data are identical, the controller702 makes the hold circuit 716 be in holding operation so that the holdcircuit 716 holds the value outputted at that time output from the colortemperature detection unit 715 and so that the hold circuit 716continues to output this value to the variable gain amplifier 707. Thatis to say, by using the same control data without newly re-performing WBcontrol, the WB control will be maintained on the video signal which isabout to be read out.

[0110] Subsequently, the controller 702 reads the video signal specifiedto be reproduced from the HDD 701 and writes it in the memory 703. Inthe similar way to the case described above, the video signal processingis carried out and the driver 712 outputs the video signal on which thereproduction processing has been performed. In this processing, asdescribed above, the WB control is performed without outputting a newsignal from the color temperature detection unit 715 to the variablegain amplifier 707 via the hold circuit 716. However, the existing valuewhich has been held at the value of the pervious output signal from thecolor temperature detection unit 715 is applied to the variable gainamplifier 707. Thus, the control signal is maintained at the constantvalue.

[0111] Now, the operation will be described below for the case where thelocation data representing the recording area associated with the videosignal which is going to be used for the WB control of the video signalto be reproduced is different from the location data stored in thecontroller 702 representing the recording area associated with thereference video signal previously used for the WB control.

[0112] In this case, the controller 702 maintains therein the locationdata representing the recording area of the video signal used forperforming the WB control and the controller 702 reads the referencevideo signal recorded in this recording area so as to write it in thememory 703. Then, the video signal written in the memory 703 is read outand the WB control is performed on it. That is to say, this time, thecontroller 702 relieves the holding operation of the hold circuit 716.Thus a new color temperature is detected and the control loop describedabove becomes in operation for controlling the variable gain amplifier707. However, in this situation, the controller 702 controls the driver712 so that the driver 712 becomes in a muting state in which thereproducing video signal is not provided from the output terminal.

[0113] When the WB control is completed in a manner as described above,the controller 702 makes the hold circuit 716 be in a holding operationso as to hold the WB control value at that time. Then, the video signalspecified to be reproduced is read out from the HDD 701 and written inthe memory 703. Then, the signal is read out from the memory 703 and isreproduction-processed without updating the WB control data.Furthermore, the controller 701 relieves the muting state of the driver712 so as to provide the reproducing video signal from the outputterminal.

[0114] When signal processing is performed on the video signal for theWB control which is carried out prior to performing of the signalprocessing on the video signal specified to be reproduced, portions ofthe video signal may be used, instead of using all of one picture dataof the video signal.

[0115] Extracting portions from the total video signal may be carriedout when the video signal is transferred from the HDD 701 to the memory703 or when the video signal is read out form the memory 703.

[0116]FIG. 10 shows a third embodiment in accordance with the presentinvention. The same or similar elements as those in the case of FIG. 7are denoted by the same numerals, and these elements will not beexplained again.

[0117] With reference to FIG. 10, the apparatus in accordance with thisembodiment has a computing circuit 717 to which the signal read out froman HDD 701 is provided. This computing circuit 717 has a variable delayline with the maximum delay time corresponding to 1 H (horizontalscanning period) of a CCD shown in FIG. 9, and performs addition betweenthe signals of different lines obtained from the CCD. There is alsoprovided a memory 718 to which the composite video signal is inputtedfrom the encoder 709. Write/read operation to and from the memory 718 isperformed under the control of the controller 702.

[0118] Now, the operation which will be performed when a command isgiven to the controller 702 to reproduce a video signal will bedescribed below. First, before reading the video signal from the HDD701, the controller 702 obtains the designation data associated with theWB control for the video signal from the data detection unit 714. Whenthe designation data obtained from the data detection unit 714designates a signal as a reference video signal which is recorded in adifferent area, this designated reference video signal should be readout first. In this reading process, the controller 702 sets the delaytime of the variable delay line to ½ H and reads the video signal fromthe HDD 701 by extracting half the horizontal line. The extracted signalis inputted to the computing circuit 717. The computing circuit 717performs addition between the data of different lines and outputs theresult to the color signal processing circuit 706 as well as to theluminance signal processing circuit 705. In the later processing, theoutput signal of the color temperature detecting unit 715 will be heldso as to produce the WB control data, and, however, at this stage, theoutput signal of the encoder 709 is not written in the memory 718.

[0119] Then, the controller 702 reads the video signal specified to bereproduced from the HDD 701 and sets the delay time of the variabledelay line in the computing circuit 717 to 1 H. The addition processingbetween different line data is performed on the video signal read out inthis way and the result is outputted. Furthermore, other processing isperformed and the composite video signal is outputted to the memory 718form the encoder 709. This time, the controller 702 controls the memory718 so that the output signal of the encoder 709 is written in thememory 718. Thus, the reproduction-processed video signal is written inthe memory 718.

[0120] Then, the controller 702 reads the video signal form the memory718. The adder 711 adds this video signal and the synchronizing signal.Then, the signal is outputted as the reproducing image signal from thedriver 712 to the monitor 713.

[0121] When it is commanded to reproduce another video signal for whichdifferent video signal is designated as the reference vide signal, thecontroller 702 continues to read the signal stored in the memory 718while the processing is performed to obtain the WB control data, untilnew control data is obtained. Then, when the signal processing on thevideo signal specified to be reproduced is performed, the controllerupdates the contents of the memory 718 so as to switch the output of thereproducing video signal. In this way, the reproducing video signal canbe switched without giving strange feeling.

[0122] Now, a fourth embodiment in accordance with the present inventionwill be described below.

[0123] In this embodiment, a plurality of video signals which designatethe same reference video signal as the reference video signal used toperform white balance control are taken into one group and arereproduced at the same time on the same screen as shown in FIG. 11. Thenumber of windows (area of sub screen) which can be displayed at thesame time may be selected from 4, 9, 16, and 25 with a window numberselection switch. As an example, multiple picture reproductioncomprising four windows A, B, C, and D as shown in FIG. 11 will bedescribed below.

[0124] With reference to FIG. 7, in such a multiple picture reproductionmode, the controller 702 reads the signal from the HDD 701 and thedesignation data is detected in the data detection unit 714. After thedesignation data, the reference video signal is read out, and then avideo signal which is designated by the designation data as that forwhich the WB control should be performed using the above reference videosignal is transferred to the area in the memory 703 corresponding to thearea A of FIG. 11. When the video signal is transferred from the HDD 701to the memory 703, reduction or partly extracting of the video signal isperformed depending on the number of the multiple reproducing windows.In this example, after reducing the data to a half for each of H and Vdirections, the reduced data is transferred to the memory 703.

[0125] Then, the controller 702 further reads from the HDD 701 thedesignated data in a different recording area and retrieves the videosignal included in the same group as that in which the video signalpreviously transferred to the memory 703 is included.

[0126] When the video signal reads the designated data of the videosignal included in the same group as a result of the retrieval,subsequently the data is reduced to ½ on this video signal for both of Hand V directions and the reduced data is transferred in the area of thememory 703 corresponding to the area B of FIG. 11. Further retrieval isrepeated so as to transfer the video signals included in the same groupto the areas corresponding to the areas C and D, respectively, afterperforming the data reduction.

[0127] In this way, when these video signals with reduced data size forfour windows having one full screen data size as a whole are stored inthe memory 703, the controller 702 starts to read the video signals fromthe memory 703 in a similar manner as in the above case. In thissituation, the period of integration processing performed in the colortemperature detection unit 715 on the R-Y and B-Y signals provided fromthe matrix circuit 708 is such a period during which the reference videosignal is read from the memory 703, that is to say, the period duringwhich the data corresponding to the area A of FIG. 11 is read out, andthus the color temperature detection is performed by using only thisreference video signal. Furthermore, the gain control of the variablegain amplifier 707 is performed via the hold circuit 716. In this way,when the operation in the control loop is settled, the controller 702makes the hold circuit 716 be in holding operation so that the holdcircuit 716 continues to provide the value which is outputted at thistime from the color detection unit 715. Based on this output value, theWB control is performed and the gain control of the variable gainamplifier 707 is controlled. Thus, the driver 712 provides the outputreproducing video signals with white balance, comprising four windows ofmultiple screens, so as to display these video signals on the monitor713 as shown in FIG. 11.

[0128] Furthermore, when a command is given to the controller 702 toswitch the reproducing signals, the controller 702 retrieves a videosignal in different recording areas again and transfers the referencevideo signal to the memory 703 so as to update the video signal in thearea corresponding to the area A. Then, retrieval is continued for thevideo signal in the HDD 701 so as to successively transfer the data tothe areas B, C, D. After that, the video signals are successively readout from the memory 703 so as to make reproduction of multiple pictures.

[0129] If the retrieval is completed for all recording areas in the HDD701 during the retrieval of the video signals, in other words, beforethe transfer of the video signals to all the areas A, B, C, and D ofFIG. 11 is completed, the controller 702 writes gray level signals inthe remaining areas.

[0130] As described above, reproduction of multiple pictures is donewith video signals belonging to a group in which all video signalsdesignate the same reference video data as the video signal to determinethe WB control data. In this reproduction, the reference video signalwhich was designated for the picture in the first window is used toperform WB control. The control data obtained in this way is held andthis same control data is further used for other pictures in multiplewindows.

[0131] When more large number of multiple windows such as 16 and 25windows is selected in the multiple picture reproduction, one fullscreen data of a video signal for performing the WB control is stored inthe memory 703 without performing any data reduction, or a predetermineddata size of video signal is stored in the memory 703. Then, this videosignal is read out from the memory 703 so as to determined the WBcontrol data and the resulting WB control data is held. After that, thevideo signals for a desired number of windows are stored in the memory703 after performing data reduction. These stored video signals are readout so as to generate reproducing video signals. In this way, good WBcontrol can be achieved even in multiple picture reproduction with alarge number of windows.

[0132] A fifth embodiment of the present invention will be describedbelow.

[0133] In this embodiment, when a picture is taken, the designation datadescribed above associated with the WB is not recorded. However, whenreproduction is performed, the selection is made for each of videosignals to be reproduced whether the video signal itself is designatedas the reference video signal or another video signal is designated asthe reference video signal. The selection switch for this purpose isprovided in the operation unit 719. In this embodiment, the circuit isconfigured as shown in FIG. 10.

[0134] When a video signal is specified to be reproduced with theoperation unit 719 and this video signal itself is designated as thereference video signal, this video signal is read out from the HDD 701and the color temperature is detected in a similar manner as in thecases described above, and further the control loop described above isestablished so as to determine the WB control data. Thus, thereproducing video signal on which WB control is performed using thiscontrol data is obtained.

[0135] As long as the WB control is performed through the control loop,the video signal which was previously processed and has been stored inthe memory 718 shown in FIG. 10 is continuously read out and displayedon the monitor 713.

[0136] Next, the operation will be described below in the case where theWB control data is obtained from the specified reference video signaland reproducing processing is carried out based on this control data.

[0137] When the operation unit 719 commands the controller 702 toreproduced multiple pictures as shown in FIG. 12, the controller 702reads video signals from the HDD 701 and performs reproductionprocessing on these signals in a manner as described above. Thus, WBcontrol and other required processing are performed on the video signalsand these video signals are written in the memory 718. In this writingprocess, after data reduction is performed on the signals outputted fromthe encoder 709 depending on the number of windows for reproduction ofmultiple pictures, the reduced video signals are stored in the memory718. With reference to FIG. 12, as an example, reproduction of multiplepictures comprising 25 windows will be described below, although thenumber of the windows is not limited to 25. In this case, the signal tobe written in the memory 718 is reduced to {fraction (1/25)}, and thenthe reduced signal is written. In this writing process, the signal isstored in the area designated by “1” located on the top and left side inFIG. 12, which is one of 25 divided areas from a full screen.

[0138] Then, another video signal is read out from the HDD 701. WBcontrol through the WB control loop is performed on this video signal,and then data reduction is carried out and the reduced video signal isstored in the area of the memory 718 shown as “2” in FIG. 2. In asimilar manner, video signals are successively stored in the memory 718at the areas corresponding to those areas denoted by “3”-“25” as shownin FIG. 12. In this way, each of video signals for 25 windows issubjected to WB control and data reduction, then written in the memory718.

[0139] When all of 25 windows are written, the controller 702 reads datafrom the memory 718 and outputs it. These signals are provided asmultiple picture video signals comprising 25 windows to the monitor 713from the driver 712 via the D/A converter 710. At this stage, watchingthe screen of the monitor 713, the operator designates a reference videosignal to be used to obtain the WB control data. This can be done byspecifying the number denoting any of the 25 divided areas.Alternatively, the desired area may be selected with a mouse.

[0140] After designating the reference video signal, the operatorselects a video signal from 25 windows to be displayed by using thecontrol data obtained from this reference video signal. When thecontroller 702 receives this command via the operation unit 719, thecontroller reads the reference video signal again from the HDD 701 andperforms WB control on this video signal in a manner as described above.After completion of WB control, the controller 702 makes the holdcircuit 716 be in holding operation so as to hold the output of thecolor temperature detection unit 715. At this time, the processedreference video signal is not written in the memory 718.

[0141] Then, the video signal selected to be reproduced is read out fromthe HDD 701 and processed. In this processing, by using the WB controldata obtained by processing the reference video signal, the gain controlis performed for each of R, G, and B signals, and then the controlledvideo signal is stored in the memory 718. When one screen of data iswritten, the data is read out and displayed on the monitor 713.

[0142] As described above, a reference video signal to be used to obtainthe WB control data is selected from video signals displayed in multiplewindows, then based on the WB control data obtained by processing theselected signal, the reproduction processing is performed on the videosignal which is selected to be reproduced. Then, this video signal isdisplayed on the monitor 713. In this example, the reference videosignal is processed again after multiple window reproduction. Instead,the controller 702 may store the control data for each of the videosignals obtained when displaying them in multiple windows so as to usethe stored control data. That is to say, the control data correspondingto the selected reference video signal is retrieved from the controldata stored in the controller 702 for each of the video signals and theobtained control data is used to control the gain of R, G, B signals forthe video signal selected to be reproduced.

[0143] A way to select a reference video signal by using a small sizewindow inserted in a full screen as in FIG. 13 will be described next.

[0144] With the operation unit 719, the above-mentioned reproductionprocessing is performed picture by picture. An operator watches thesepictures on the monitor 713. At this stage, the operator can designate avideo signal reproduced on the monitor 713 as a reference video signalto be used to obtain control data. This designation can be done byoperating the WB selection switch provided on the operation unit 719. Ifthis WB selection switch is operated, the control data used forprocessing this video signal displayed on the monitor 713 is held in thehold circuit 716. Furthermore, data is written in the memory 718 so thatthe video signal reproduced at that time on the screen may be displayedin the small window denoted by A in FIG. 13.

[0145] Subsequently, when another video signal is newly selected to bereproduced, this selected video signal is signal-processed using thecontrol data for the video signal displayed in the small window area A,then the selected video signal is stored in the memory 718. Then, thesignal is read out from the memory 718, and thus the monitor output isobtained. In this case, reading from the memory 718 is done so that thereproducing signal may be displayed in the area denoted by B in FIG. 13.Display on the monitor 703 is done such that the video signal used toobtain the control data is displayed in the small window area A, and thevideo signal which is WB-controlled by suing the control data obtainedfrom the video signal displayed in the small area is displayed in thearea B.

[0146] When another video signal is further newly selected to bereproduced, the selected video signal is displayed in the area B. Whenanother different video signal is designated as the signal used toobtain the control data, this newly designated video signal is displayedin the small window area A instead of the previous one, and the controldata is also replaced with the new control data obtained from this newvideo signal.

[0147] In each of the above embodiments, WB control is performed byusing the integrated value of the color difference signals. However, WBcontrol method is not limited to that. It may also be performed by usingR, G, B signals.

[0148] The recording medium for recording the video signals is notlimited to a hard disk, however, another medium such as a memory card, amagnetic sheet, a magnetic tape, and an optical disk may also be used.

[0149] In accordance with the second embodiment of the invention, asdescribed above, WB control in reproduction of a video signal isperformed by using control data obtained from a reference video signaldesignated when the video signal is recorded. Thus, an image of anobject even having a large magnitude of color-difference components maybe reproduced with good WB control under the same color temperature, bydesignating the video signal as the reference video signal which isobtained by taking a picture of an object having a small magnitude ofcolor difference such as a white object. In this way, high accuracy WBcontrol is possible in reproduction and even an object having a largemagnitude of color difference components may be reproduced without anyloss of vividness in color.

[0150] In the arrangement according to the third embodiment of theinvention, as described above, when video signals recorded on arecording medium are reproduced, an arbitrary video signal may bedesignated as a reference video signal to obtain WB control data. As aresult of this, even video signals for which high accuracy WB controlwould be impossible by themselves may be reproduced with good enough WBcontrol. In particular, if a picture of a colorless object such as whitepaper is taken with illumination of the same light source as that withwhich pictures of usual objects are taken, ideal WB control is possiblein reproduction-processing of these usual objects by designating theabove video signal of white paper as the reference video signal.

[0151] In the arrangement according to the fifth embodiment, a referencevideo signal and other video signals are displayed in multiple windowareas, thus it is possible to make quick retrieval or checking on videosignals which are obtained by taking their pictures under similarconditions.

[0152] Now, a sixth embodiment in accordance with the present inventionwill be described hereinbelow.

[0153] In automatic WB control method according to the first embodimentdescribed earlier, when a picture is taken of a distant object with alens having a large focal length, there may be difference in lightsource between the location of a camera and the location of the object.In such a case, in the arrangement with the external sensor describedabove, because the color of light in the outside is measure at thelocation of the camera, WB correction on the object is impossible. Onthe other hand, in the TTL method described earlier, the color of theobject itself leads to large influence. For example, in some cases wherean enlarged picture is taken of a monochromatic object with a lenshaving a large focal length, the color correction is performed on thecolor of the object itself and no WB correction occurs on the object.

[0154] With the imaging apparatus according to this embodiment, wrongautomatic WB correction can be avoided even in the case of the longfocal length, which will be described in more detail hereinbelow.

[0155] In this embodiment, an electronic still camera will also be takenas an example to which the present invention is adapted. The circuitconfiguration shown in FIG. 1 is used in the embodiment. With referenceto the flow chart shown in FIG. 14, WB control in accordance with thisembodiment will be described next.

[0156] First, in step S141, decision is made whether a switch SW1 (14)is on, and if the conclusion is positive, the routine proceeds to stepS142 in which the color is measured with a color sensor 24. Further, instep S143, decision is made whether a switch SW2 (15) is on, and if theconclusion is positive, the routine proceeds to step S144, and if theconclusion is negative, the routine returns to step S141. In step S144,the focal length of the camera lens 1 is locked and this focal length isread with a system controller 11, and then the routine proceeds to stepS145.

[0157] In step S145, depending on the focal length obtained in stepS144, the system controller 11 modifies the color data obtained in stepS142, and then the routine proceeds to step S146. In step S146, thesystem controller 11 controls a memory controller 9 so as to perform WBcorrection on the taken image with an image processor 27. Finally, anactual picture is taken.

[0158] In arrangement with the external sensor, when the measured valuewith the color sensor 24 is near to the daylight color, the color datais not modified even if the focal length changes, and in other cases,the color data is limited or modified depending on the change in focallength. In the TTL method, when the measured color value is near to thatof color of light source such as daylight, a lamp, and a fluorescentlamp, the color data is not modified regardless of the change in thefocal length, and in other cases, the color data is limited or modifieddepending on the change in the focal length. In the case of hybridmethod, the color measured with the color sensor 24 is compared with thecolor measured with TT1. When both measured values are similar to eachother, the color data is not modified even if the focal length changes,and in other cases, the color data is limited or modified depending onthe change in the focal length.

[0159] In the arrangement in accordance with this embodiment, the colordata is modified depending on the focal length of the camera lens so asto avoid the wrong WB correction occurring in particular when the focallength is large. Thus, good WB is always achieved in reproduction ofpictures.

[0160] A seventh embodiment in accordance with the present inventionwill be described hereinbelow.

[0161] In addition to the problems described above in the arrangementwith the external sensor or TT1, there are possible problems asdescribed below.

[0162] In the external WB method, the accuracy of WB control isinfluenced by the ambient colors and also by the fact that the directionof the light source illuminating an object is not always constant. As aresult, the perfect WB reproduction is impossible.

[0163] In the TTL method, when a picture is taken in a situation wherethe color temperature of the light source changes quickly with time asin the case a picture is taken in the natural light in the morning orevening, WB control data obtained by taking a picture of a referencereflection board may be different from that which would be obtained atthe real time when an actual still picture is taken, and thus there mayexist large errors in WB control in which the error may increase withtime.

[0164] There will be described hereinbelow an imaging apparatusaccording to this embodiment, which provides a solution to the aboveproblems.

[0165]FIG. 15 is a block diagram showing a configuration of anelectronic still camera in accordance with this embodiment. In FIG. 15,there are shown a camera lens 151, an image sensor 152 such as a CCD, anA/D converter 153 for converting the output signals provided from eachpixel of the image sensor 152 into a digital signal, an RGB processingcircuit 155 for processing the digital pixel data from the output of theA/D converter 153 so as to obtain RGB digital data, a recording medium156 for recording the RGB digital data from the output of RGB processingcircuit 155, and a dating circuit 157 for providing time datarepresenting a date and time.

[0166]FIG. 16 shows a color filter arranged in front of the image sensor152. As shown, this filter comprises Mg (magenta), G (green), Cy (cyan),and Ye (yellow) disposed for each pixel in additive complementary colorarrangement.

[0167] The operation will be described next.

[0168] Before an actual still picture is taken, a picture of a neutralgray reference reflection board is taken and this image is recorded onthe recording medium 156 as WB control data together with the time datagiven from the dating circuit 157. In a case where a plurality ofpictures are taken with illumination from the same light source (such asstudio illumination and flash lamp) under the same condition, the aboveWB control data may be used in reproduction for all of these stillpictures. In this case, the time data may be used to determine which WBcontrol data should be used.

[0169] On the other hand, in a case where the condition of the lightsource changes quickly with time (as in the case a picture is taken inthe natural light in the morning or evening), after the last stillpicture is taken, a picture of the reference reflection board is takenagain to produce the WB control data and the WB control data is recordedtogether with the time data.

[0170]FIG. 17 shows WB control data in a 2-dimensional fashion whereinthe levels of R (red) and B (blue) are represented by horizontal andvertical axes, respectively. In FIG. 17, the color temperature goes downto the right and down, and goes up to the left and up.

[0171] As an example, let us take the case where the color temperatureof the light source decreases with time as in the evening. In FIG. 17,“WB1” denotes the WB control data which was obtained by taking a pictureof the reference reflection board before actual pictures were taken.“WB2” denotes the WB control data which was obtained by taking a pictureof the reference reflection board at the time the color temperaturedecreased after actual pictures were taken. The still pictures whichwere taken between two measurements of the WB control data exist between“WB1” and “WB2” in FIG. 17.

[0172] When the pictures are reproduced, the WB control data WB1 and WB2are determined judging from the time data, and points between two WB1and WB2 are selected by proper computation. Then, these selected pointsare used as the WB control data so as to achieve better WB control. Onthe hand, when it is desired to preserve the effect of the “brightcolors of the sunset” and to shift the colors toward the amber-basedcolors, similar processing is performed between WB2 and WB0 which is onthe extension of the segment of the line with WB1 and WB2 so as toachieve the above purposed.

[0173] To obtain the WB control data, it is not necessary to use allpixel data comprising a full size picture. Instead, for example, it maybe good enough to record just data associated with 8×8 pixels in acentral part of a picture for this purpose. Alternatively, the averagevalue of R and B data corresponding to about 10 pixels in a central partof a picture may be used to achieve this purpose.

[0174] In each case, management on the WB control data may be done byusing ID data such as a frame number instead of the time data. In thiscase, the dating circuit 157 is not required. It should be understoodthat the frame number or other similar data is also herein denoted bythe term “time data”.

[0175] In the embodiments described above, it has been assumed that theimage sensor 152 is provided with color filters disposed in the additivecomplementary color arrangement and there is provided the RGB processingcircuit 155. However, the average values of Ye, Cy, and G data in acentral part of a picture may be directly recorded as WB control datapreserving additive complementary colors. Then, when the picture isreproduced, the R and B values may be calculated from these data asfollows: R═Ye-G, B═Cy-G. (It should be noted that the above equations donot include coefficients.) In this case, the circuit may be configuredas shown in FIG. 18, wherein a switch 160 (multiplexer) is provided forswitching the signals.

[0176] When the image sensor 152 uses the color filters arranged withRGB primary colors as shown in FIG. 19, the RGB processing circuit 155is not required both in taking a picture and in obtaining WB controldata. In this case, the circuit may be configured as shown in FIG. 20.

[0177] With the arrangement in accordance with this embodiment, the WBcontrol data is detected and recorded together with the time data.Furthermore, when the WB control data is required to be detected inreproduction, the still picture is identified by using the time data,and the WB adjustment can be accurately performed by using thecorresponding WB control data.

[0178] Moreover, in another aspect of this embodiment, the WB controldata are detected before and after taking pictures, and the obtained WBcontrol data are recorded together with the time data. These two WBcontrol data can be used to perform proper WB adjustment for a pluralityof the still pictures which were taken with illumination of a lightsource changing with the time between these WB control data.

1. A conversion method characterized by displaying at least one sensedimage; setting a standard data based on the displayed sensed image;storing the standard data set; and converting another sensed image basedon the standard data stored.
 2. A conversion method of claim 1characterized by that the sensed image set as said standard data is animage photographing an object of achromatic color.
 3. A conversionmethod of claim 1 characterized by that the sensed image set as saidstandard data is a part of an image photographing an object ofachromatic color.
 4. A recording apparatus characterized by having asensed image input device for inputting a sensed image; an inputtingdevice of a standard image for color processing of said sensed imagewhich-inputs the standard image for color processing of said sensedimage; and a recording device which records an information correspondingto the standard image for color processing of said sensed image,connecting it with another sensed image.
 5. A recording apparatus ofclaim 4 characterized by that the standard image for color processing ofsaid sensed image is an image photographing an object of achromaticcolor.
 6. A recording apparatus of claim 5 characterized by that theinformation corresponding to the standard image for color processing ofsaid sensed image is a control value of white balance obtained from theimage photographing said object of achromatic color.
 7. A recordingapparatus of claim 5 characterized by that the information correspondingto the standard image for color processing of said sensed image is apart of the image photographing said object of achromatic color.
 8. Arecording apparatus of claim 4 characterized by that said sensed imageis processed based on the information corresponding to the standardimage for color processing of said sensed image.
 9. A reproducingapparatus characterized by having a reading out device which reads aninformation recorded together with another sensed image, andcorresponding to a standard image for color processing of sensed imageout of a recording medium; and a reproducing device which reproducesanother sensed image based on the information corresponding to thestandard image for color processing of said sensed image which is readout.
 10. A reproducing apparatus of claim 9 characterized by that thestandard image for color processing of said sensed image is an imagephotographing an object of achromatic color.
 11. A reproducing apparatusof claim 10 characterized by that the information corresponding to thestandard image for color processing of said sensed image is the controlvalue of white balance obtained from the image photographing said objectof achromatic color.
 12. A reproducing apparatus of claim 10characterized by that the information corresponding to the standardimage for color processing of said sensed image is a part of the imagephotographing said object of achromatic color.
 13. A reproducingapparatus of claim 9 characterized by that said sensed image isprocessed based on the information corresponding to the standard imagefor color processing of said sensed image.
 14. A recording methodcharacterized by: inputting a sensed image; inputting a standard imagefor color processing of said sensed image for inputting the standardimage for color processing of said sensed image; and recording aninformation corresponding to the standard image for color processing ofsaid sensed image together connecting it with another sensed image. 15.A recording method of claim 14 characterized by that the standard imagefor color processing of said sensed image is an image photographing anobject of achromatic color.
 16. A recording method of claim 15characterized by that the information corresponding to the standardimage for color processing of said sensed image is the control value ofwhite balance obtained from the image photographing said object ofachromatic color.
 17. A recording method of claim 15 characterized bythat the information corresponding to the standard image for colorprocessing of said sensed image is a part of the image photographingsaid object of achromatic color.
 18. A recording method of claim 14characterized by that said sensed image is processed based on theinformation corresponding to the standard image for color processing ofsaid sensed image.
 19. A reproducing method characterized by that itreads an information recorded together with another sensed image, andcorresponding to a standard image for color processing of the sensedimage out of a recording medium; and it reproduces another sensed imagebased on the information corresponding to the standard image for colorprocessing of said sensed image which is read out.
 20. A reproducingmethod of claim 19 characterized by that the standard image for colorprocessing of said sensed image is an image photographing an object ofachromatic color.
 21. A reproducing method of claim 20 characterized bythat the information corresponding to the standard image for colorprocessing of said sensed image is the control value of white balanceobtained from the image photographing said object of achromatic color.22. A reproducing method of claim 20 characterized by that theinformation corresponding to the standard image for color processing ofsaid sensed image is a part of the image photographing said object ofachromatic color.
 23. A reproducing method of claim 19 characterized bythat said sensed image is processed based on the informationcorresponding to the standard image for color processing of said sensedimage.
 24. A recording medium recording a program for executing therecording method of claim
 14. 25. A recording medium recording a programfor executing the reproducing method of claim 19.